To examine a number of slides of patients from the mid 1970's whose subsequent course is known to see if our TK antibodies reveal abnormalities consistent with the known history. To assay fresh surgical specimens using TK and PRPP synthetase antibodies and correlate these results with other laboratory and clinical data. To attempt to prepare monoclonal antibodies that may enhance the specificity and sensitivity of these antibodies. We shall attempt to purify the factor in tumors that enhances the action of DCF and the inhibitor of ODC in colonic mucosal.